In recent years, a strongly increasing demand for high transmission bandwidths within wireless communication systems is observed. To achieve a higher data throughput some modern cellular communication systems like LTE (long term evolution) and UMTS (Universal Mobile Telecommunications System) have increased the transmission bandwidth over those that can be supported by originally defined single channel or carrier. This multi-carrier method being proposed is generally termed Carrier Aggregation (CA). Those carriers can be allocated contiguous or non-contiguous in the same band (intraband CA) or even in different bands (interband CA). The information transmitted through all these carriers has to be recovered at the receiver. It is desired to recover information transmitted through various channels with low spurious generation at low power consumption and with low hardware efforts.